Limit thread priority and scheduling
The Java threading model involves thread priority that can be changed dynamically. Essentially, the priority of a thread is a number from 1 to 10, and the larger the number indicates the more urgent the task is. The JVM standard calls threads with higher priority first, and then calls threads with lower priority. However, the standard's processing of threads with the same priority is random. How to deal with these threads depends on the operating system policy of the grassroots level. In some cases, threads with the same priority run time-sharing; in others, the threads will run until the end. Remember that Java supports 10 priorities, and grassroots operating systems may support much less priorities, which can cause some confusion. Therefore, priority can only be used as a very rough tool. The final control can be accomplished by using the yield() function wisely. Normally, please do not rely on thread priority to control the state of the thread.
summary
This article explains how to use threads in Java programs. More important questions like whether or not you should use threads depend on the application at hand in a large way. One way to decide whether to use multithreading in an application is to estimate the amount of code that can be run in parallel. And remember the following points:
Using multithreading will not increase the CPU's capabilities. But if implemented using local threads of the JVM, different threads can run simultaneously on different processors (in multi-CPU machines), thus making the multi-CPU machines fully utilized.
If the application is compute-intensive and constrained by CPU functionality, only multiple CPU machines can benefit from more threads.
Multithreading is often advantageous when an application has to wait for slow resources (such as a network connection or database connection), or when the application is non-interactive.
Internet-based software needs to be multi-threaded; otherwise, users will feel that the application is slow to respond. For example, multithreading can make programming easier when developing servers that support a large number of clients. In this case, each thread can serve different clients or client groups, thus reducing response time.
Some programmers may have used threads in C and other languages, where there is no language support for threads. These programmers may usually be made to lose confidence in threads.
The Java threading model involves thread priority that can be changed dynamically. Essentially, the priority of a thread is a number from 1 to 10, and the larger the number indicates the more urgent the task is. The JVM standard calls threads with higher priority first, and then calls threads with lower priority. However, the standard's processing of threads with the same priority is random. How to deal with these threads depends on the operating system policy of the grassroots level. In some cases, threads with the same priority run time-sharing; in others, the threads will run until the end. Remember that Java supports 10 priorities, and grassroots operating systems may support much less priorities, which can cause some confusion. Therefore, priority can only be used as a very rough tool. The final control can be accomplished by using the yield() function wisely. Normally, please do not rely on thread priority to control the state of the thread.
summary
This article explains how to use threads in Java programs. More important questions like whether or not you should use threads depend on the application at hand in a large way. One way to decide whether to use multithreading in an application is to estimate the amount of code that can be run in parallel. And remember the following points:
Using multithreading will not increase the CPU's capabilities. But if implemented using local threads of the JVM, different threads can run simultaneously on different processors (in multi-CPU machines), thus making the multi-CPU machines fully utilized.
If the application is compute-intensive and constrained by CPU functionality, only multiple CPU machines can benefit from more threads.
Multithreading is often advantageous when an application has to wait for slow resources (such as a network connection or database connection), or when the application is non-interactive.
Internet-based software needs to be multi-threaded; otherwise, users will feel that the application is slow to respond. For example, multithreading can make programming easier when developing servers that support a large number of clients. In this case, each thread can serve different clients or client groups, thus reducing response time.
Some programmers may have used threads in C and other languages, where there is no language support for threads. These programmers may usually be made to lose confidence in threads.